Paste two versions of a text and instantly see what changed — added, removed, or modified. Switch between side-by-side and unified view.
Original text
Modified text
Added
Removed
Differences
Paste text in both fields above to compare
How to use the Text Diff Checker
Paste the original version of your text in the left field and the modified version in the right field. Differences are highlighted instantly — green for added content, red for removed content. Switch between "Side by side" and "Unified" views using the buttons at the top.
Use "Ignore case" to treat uppercase and lowercase as identical. Use "Ignore whitespace" to skip differences caused only by spaces or indentation changes.
Common use cases
Document review — compare two versions of a contract, article, or report to find what changed between drafts.
Code review — spot changes in configuration files, scripts, or any plain-text code.
Content editing — compare original and edited versions of blog posts or marketing copy.
Translation check — compare a source text to a translated version line by line.
Frequently asked questions
Side-by-side shows the original and modified text in two columns, making it easy to compare corresponding lines visually. Unified view shows both in a single column with additions marked in green and removals in red — similar to the output of the Unix "diff" command.
This tool uses the Longest Common Subsequence (LCS) algorithm to find the minimum set of changes needed to transform one text into another. It compares line by line, then within changed lines performs word-level comparison to highlight exactly which words changed.
No hard limit. Very large texts (thousands of lines) may take a moment to process as diff computation is intensive, but all processing runs locally in your browser.
No. Everything runs in your browser. Your text never leaves your device.